Introducing dogs to one another
Introducing a new dog into a home that already has one can be challenging. Canines must establish a "pecking order", with the most dominant animal becoming pack leader. If you bring a second or third dog into your home, this is the first issue the dogs will resolve. The key is to make sure it happens with minimal discord. Under close human supervision, this difficult but necessary aspect of canine behaviour can be accommodated with minimal fuss.
1) When you bring the new dog into your home, make sure your current is confined to a specific section of the house, out of sight,
2) Allow the new dog to roam the house for several hours. The new dog will scent the current dog and become aware that it is not alone.
3) Introduce the two dogs - not in your home but on neutral ground. Try the sidewalk in front of your home. This will eliminate issues of territorial defense. Both animals should be leashed. If the dogs are large, enlist another person to help
4) If the dogs appear to tolerate each other, take them both back to the house. However, do not leave them alone together. It can take weeks or even months for the dogs to develop a healthy relationship; until that happens, they should interact only under your direct supervision.
5) If the dogs do not tolerate each other, try briefly crating the new dog and giving your current dog the run of the house. Then briefly crate the original dog and let the new one out. After they become more familiar with each other, release both dogs and allow them to interact under your supervision.
6) If the dogs fight, do not try to separate them with your hands. For smaller dogs use a squeeze bottle of water to temporarily distract both canines. Larger dogs should have leashes on so they can be pulled apart.
7) Give each dog separate food and water bowls, separate beds, and separate crates. Sharing such personal things may cause strife.
8) Once your dogs establish a pecking order, respect it. Greet the pack leader first when you arrive home (it will be obvious who is the pack leader). This dog should also be fed first and should receive preferred access to treats and attention. Ignoring the pecking order may cause the dogs to become confused and agitated.